1. National Laboratory of Solid-State Microstructures, School of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
2. School of Physics, Communication and Electronics, Jiangxi Normal University, Nanchang 330022, China
3. Department of Materials Science and Engineering, Harbin Institute of Technology, Shenzhen, Guangdong 518055, China
4. Department of Applied Physics, College of Science, Nanjing Forestry University, Nanjing 210037, China
5. Institute for Advanced Materials, Hubei Normal University, Huangshi 435100, China